For the last 235 years, on the Fourth of July, Americans have celebrated the birth of the United States, and the founding ideas that have made it the most powerful, wealthiest and freest nation in the history of civilization.

But as another July 4 dawns, there has never been more uncertainty about the future of America — and the anxiety transcends even the dismal economy and three foreign wars. President Obama prompted such introspection in April 2009, when he suggested that America, as one of many nations, was not necessarily any more exceptional than others. Recently, a New Yorker magazine article sympathetically described our new foreign policy as “leading from behind.”

The administration not long ago sought from the United Nations and the Arab League — but not from Congress — authorization to attack Col. Khadafy’s Libya. Earlier, conservative opponents had made much of the president’s bows to Chinese and Saudi Arabian heads of state, which, coupled with serial apologies for America’s distant and recent past, were seen as symbolically deferential efforts to signal the world that the United States was at last not necessarily pre-eminent among nations.

Yet, there has never been any nation even remotely similar to America. Here’s why. Most revolutions seek to destroy the existing class order and use all-powerful government to mandate an equality of result rather than of opportunity — in the manner of the French Revolution’s slogan of “liberty, equality and fraternity” or the Russian Revolution’s “peace, land and bread.”

In contrast, our revolutionaries shouted “Don’t tread on me!” and “Give me liberty or give me death!” The Founders were convinced that constitutionally protected freedom would allow the individual to create wealth apart from government. Such enlightened self-interest would then enrich society at large far more effectively than could an all-powerful state.

Such constitutionally protected private property, free enterprise and market capitalism explain why America — with only about 4.5 percent of the world’s population — even today, in an intensely competitive global economy, still produces a quarter of the world’s goods and services. To make America unexceptional, inept government overseers, as elsewhere in the world, would determine the conditions — where, when, how and by whom — under which businesses operate.

Individual freedom in America manifests itself in ways most of the world can hardly fathom — whether our unique tradition of the right to gun ownership, the near impossibility of proving libel in US courts, or the singular custom of multimillion-dollar philanthropic institutions, foundations and private endowments. Herding, silencing or enfeebling Americans is almost impossible — and will remain so as long as well-protected citizens can say what they want and do as they please with their hard-earned money.

Race, tribe or religion often defines a nation’s character, either through loose confederations of ethnic or religious blocs as in Rwanda, Iraq and the former Yugoslavia, or by equating a citizenry with a shared appearance as reflected in the German word “volk” or the Spanish “raza.” While America was originally crafted largely by white males who improved upon Anglo-Saxon customs and the European Enlightenment, the Founders set in place an “all men are created equal” system that quite logically evolved into the racially blind society of today.

This year, a minority of babies born here will resemble the look of the Founding Fathers. Yet America will continue as it was envisioned, as long as those of various races and colors are committed to the country’s original ideals.

The Founders’ notion of the rule of law, coupled with freedom of the individual, explains why America runs on merit, not tribal affinities or birth. Most elsewhere, being a first cousin of a government official, or having a prestigious name, ensures special treatment from the state. Yet in America, nepotism is never assured. End that notion of American merit and replace it with racial tribalism, cronyism or aristocratic privilege, and America itself would vanish as we know it.

There is no rational reason why a small republican experiment in 1776 grew to dominate global culture and society — except that America is the only nation, past or present, that put trust in the individual rather than in the state and its elite bureaucracy. Such confidence in the average free citizen made America absolutely exceptional — something we should remember more than ever on this July 4.